getting ready to do front/rear diffs & x-fer case fluid change & was wondering what type of lube others use in the xfr case?

i did a search & not much comes up specific to 4th gens using synthetic vs conventional. anyone think theres a issue using synthetic in the x-fer case? mainly regarding leaks. i read one post where a guy said he got a leak at the actuator a week or 2 after using synthetic, but even he said since leaks there are so common he cant say if it was because of the synthetic.

just curious if anyone has had any problems using synthetic in the xfr case or the diffs.

Did all 3 of mine and haven’t had any issues, I actually think it is quieter and gave me an extra 1 mpg. So far.

Differentials and Transfer Case-can I use synthetic?

Synthetic Gear-Oil for Diff - Question

What oil to use for differentials and transfer case? Delvac? - Toyota 4Runner Forum - Largest 4Runner Forum

Transfer case concerns

Transfer Case, Differential Fluid Change

thanks for the links. i read a few of those when i did a search but didnt see the "transfer case concerns" thread, which is really the only one to discuss leaks from synthetic in the x-fer case. the other threads are all 5-10 years old & just talk about using synthetic in general or what brand or version of a brand to use.

the search function doesn't always work like you want based on search words used, or they are all very old threads you have to sift through & dont always address your specific concern.

sounds like synthetics are ok to use if no major leaks have popped up over the years.

I did my transfer and diffs a couple years ago and put conventional back into them, just for piece of mind. I had about 90k miles on it and that was with all original fluids.
My reasoning for using conventional was:
- All seals/bushings/whatever else may be in there that can react with the oil has gotten used to whatever type of oil was previously run. So I'll just keep using that.

For the same reason I don't run full synthetic motor oil either, as I started using conventional or synthetic blends, so I will keep using these.

Been doing regular changes with mobile 1 synthetic 75w90 and the newer mobile 1 Devlac for several years. Seems to work fine, I couldn't see any reason not to do it.
I use the same in the diffs as well. Regular changes are more important then what you use believe it or not.

https://www.amazon.com/dp/B007WVI5G6...v_ov_lig_dp_it

Hi All,

I have been reading up on changing the diff (front/back) and transfer case fluids on 4runners and have come across a lot of great information on here. Overall seems to be a fairly easy job and based on the info shared in multiple threads I have a solid understanding of the tools/parts needed. There is however one question I was unable to find an answer on (yes, may have missed it) that I was hoping you seasoned pros could help me with.

Looking at the part numbers for the gaskets it seems the following are what comes up on here and most places:

Transfer Case Fill Gasket 90430-18008
Transfer Case Drain Gasket 90430-18008
Front Differential Fill Gasket 12157-10010
Front Differential Drain Gasket 90430-24003
Rear Differential Fill Gasket 12157-10010
Rear Differential Drain Gasket 12157-10010


My questions is....on my 4runner (03 V8 Sport) will these work? When I look it up online on dealer site it seems to indicate there is a difference and the part numbers are:

Transfer Case Fill Gasket 90301-56009 (confirmed this is incorrect)
Transfer Case Drain Gasket 90301-56009 (confirmed this is incorrect)
Front Differential Fill Gasket 12157-10010
Front Differential Drain Gasket 90430-24003
Rear Differential Fill Gasket 12157-10010
Rear Differential Drain Gasket 12157-10010

UPDATE
In case it happens to anyone else I did track down the issue on the site I was looking at. Apparently the 90430-18008 is no longer correct (according to them) and its now 90430-A003.

Also where do you recommend getting the parts? I have a local dealer but Id prefer not to go that route...havent had good luck with them.

Thanks!

I assume you read this post since you already have part numbers, but its here in case someone else lands on this post: Changing Differential & Transfer Case Fluids - Pics Included

I got my crush washers from Amazon. They're not Toyota gaskets, but I haven't had any trouble with them leaking. They came with 2 whole sets, so I taped the other set to my extra gear oil bottle so I wouldn't lose them. They're these here: Amazon.com: 12pcs Transfer and Differential Fill/Drain Plug Gaskets Fit for Toyota Lexus 4Runner Land Cruiser Tundra Tacoma FJ Cruiser Highlander RAV4 Sequoia Sienna, Replace # 90430-18008 12157-10010 90430-24003: Automotive. Excuse the napkin pic, but I made this for myself to show where they all go. RD = rear drain, RF = rear fill, TD = tcase drain, etc.


For gear oil, I used mobile 1 full syntheric 75w-90 in front, rear, and transfer case. Got 4 x2 packs, for a total of 8qts, because it as the cheapest I could find them. Pretty much anything for under $12/qt for good stuff is a good deal. I got mine on amazon here: Amazon.com: Mobil 1 104361 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2): Automotive

The front diff is a pain, grind the 10mm hex socket end flat. Most hex bits have a little chamber on the end to allow them to go in easier, but grinding that off that will allow it to grip better. Mine was really stuck and I had to weld a nut on there.

Ill be tackling this tomorrow if everything goes to plan...hoping I have a little better luck with the front diff!

@03v84Running , this post may be helpful though I can’t say with 100% certainty that the parts are the same on the ‘03 & ‘07 models.

Looks like the wrong link? That was just a "hey I bought a 4R!" post

Sent from my Pixel 3 XL using Tapatalk

I just tested it again & it works. Should be a pic of the gaskets labeled with where they go. It’s post #346 in the “Changing Differential Oil...” thread linked by y=mx+b.

Edit: here’s the pic: